Although previous research on age-related changes in immune function have concentrated on the deficiency of factors that can augment cellular function, it is now apparent that the levels of many lymphokines, cytokines, and inflammatory factors are elevated in spleen cell culture supernatants from old mice. These factors, IL-6, TGF beta, and IFN alpha can disrupt cellular function. The causes of the elevations are not known, but demonstrate that cells from old mice are not deficient in their ability to make factors. In old rats, factors such as TGF beta and IL-6 many explain the differences seen in bone marrow cellular response to trauma.